Olá! Estou testando a nova versão beta 13.04 do Ubuntu e estou tendo problemas com alguns erros de importação do virtualenv. Tive esta saída ao tentar construir o firefox:

Creating Python environment
Cannot find file /usr/include/x86_64-linux-gnu/python2.7 (bad symlink)
New python executable in /home/marco/bernardo/FD/src/obj-x86_64-unknown-linux-gnu/_virtualenv/bin/python2.7
Not overwriting existing python script /home/marco/bernardo/FD/src/obj-x86_64-unknown-linux-gnu/_virtualenv/bin/python (you must use /home/marco/bernardo/FD/src/obj-x86_64-unknown-linux-gnu/_virtualenv/bin/python2.7)
Installing setuptools...................................
  Complete output from command /home/marco/bernardo...ualenv/bin/python2.7 -c "#!python
\"\"\"Bootstra...sys.argv[1:])

" /home/bernardo/bernardo...ols-0.6c11-py2.7.egg:
  Traceback (most recent call last):
  File "<string>", line 278, in <module>
  File "<string>", line 239, in main
  File "/home/bernardo/bernardo/FD/src/python/virtualenv/virtualenv_support/setuptools-0.6c11-py2.7.egg/setuptools/command/easy_install.py", line 1712, in main
  File "/home/marco/bernardo/FD/src/python/virtualenv/virtualenv_support/setuptools-0.6c11-py2.7.egg/setuptools/command/easy_install.py", line 1700, in with_ei_usage
  File "/home/marco/bernardo/FD/src/python/virtualenv/virtualenv_support/setuptools-0.6c11-py2.7.egg/setuptools/command/easy_install.py", line 1716, in <lambda>
  File "/usr/lib/python2.7/distutils/core.py", line 152, in setup
    dist.run_commands()
  File "/usr/lib/python2.7/distutils/dist.py", line 953, in run_commands
    self.run_command(cmd)
  File "/usr/lib/python2.7/distutils/dist.py", line 971, in run_command
    cmd_obj.ensure_finalized()
  File "/usr/lib/python2.7/distutils/cmd.py", line 109, in ensure_finalized
    self.finalize_options()
  File "/home/marco/bernardo/FD/src/python/virtualenv/virtualenv_support/setuptools-0.6c11-py2.7.egg/setuptools/command/easy_install.py", line 125, in finalize_options
  File "/home/marco/bernardo/FD/src/python/virtualenv/virtualenv_support/setuptools-0.6c11-py2.7.egg/setuptools/command/easy_install.py", line 1121, in _expand
  File "/usr/lib/python2.7/distutils/cmd.py", line 312, in get_finalized_command
    cmd_obj.ensure_finalized()
  File "/usr/lib/python2.7/distutils/cmd.py", line 109, in ensure_finalized
    self.finalize_options()
  File "/home/marco/bernardo/FD/src/python/virtualenv/virtualenv_support/setuptools-0.6c11-py2.7.egg/setuptools/command/install.py", line 32, in finalize_options
  File "/usr/lib/python2.7/distutils/command/install.py", line 321, in finalize_options
    (prefix, exec_prefix) = get_config_vars('prefix', 'exec_prefix')
  File "/home/marco/bernardo/FD/src/obj-x86_64-unknown-linux-gnu/_virtualenv/lib/python2.7/distutils/__init__.py", line 92, in sysconfig_get_config_vars
    real_vars = old_get_config_vars(*args)
  File "/usr/lib/python2.7/distutils/sysconfig.py", line 503, in get_config_vars
    func()
  File "/usr/lib/python2.7/distutils/sysconfig.py", line 447, in _init_posix
    from _sysconfigdata import build_time_vars
  File "/usr/lib/python2.7/_sysconfigdata.py", line 6, in <module>
    from _sysconfigdata_nd import *
ImportError: No module named _sysconfigdata_nd
----------------------------------------
...Installing setuptool...

Procurando algum tipo de solução, encontrei este ticket no Ubuntu's mas tracker descrevendo o mesmo problema que eu estava tendo. Lendo os comentários, houve uma solução alternativa para corrigir o problema, mas também havia um comentário dizendo que este é um problema do virtualenv, como você pode ver aqui . Achei que seria bom abrir este tíquete para ver se posso ajudar em algo.